The invention relates to conversion of biomass to a liquid hydrocarbonaceous fuel, particularly to an apparatus for converting biomass to a pumpable slurry, and more particularly to an apparatus for hydrolyzing lignocellulosic materials, particularly wood chips, in a pressure vessel having no moving parts.
Various types of apparatus have been developed for utilizing biomass, such as wood chips, for a variety of applications. These prior known apparatus are exemplified by U.S. Pat. No. 3,298,899 issued Jan. 17, 1967, to O. A. Laakso; U.S. Pat. No. 3,586,600 issued June 22, 1971, to J. P. Rich et al; U.S. Pat. No. 4,002,528 issued Jan. 11, 1977, to O. A. Laakso; and U.S. Pat. No. 4,025,356 issued May 24, 1977, to G. A. Nyman et al. These prior apparatus include a single-pass type pressure vessel in which the biomass is digested or broken down to the desired size, etc., as exemplified by above-referenced U.S. Pat. Nos. 3,298,899 and 3,586,600.
Recently, substantial effort has been directed to processes and apparatus for the production of fuel from biomass. The known apparatus for converting biomass, such as wood chips, wood pulp, newspapers, etc., had considerable difficulty with clogging of pipes, etc., because there was no suitable inexpensive means for producing a slurry from the chips. Also the prior apparatus utilized pressure vessels with seals for the introduction of rotating shafts, etc., for circulating or pressurizing the material as it passes through the pressure vessel. Such an apparatus is described in C & EN News, Vol. 20, Oct. 8, 1979, entitled "Continuous Cellulose-to-Glucose Process". A constant maintenance problem has resulted from the breakdown of these pressure vessel seals. Thus, substantial time and effort have been directed to resolving this maintenance problem.